March 2015

NSIDC

In the past couple of days organisations like the NSIDC, NASA and NOAA have announced the annual event of the Arctic sea ice pack reaching its largest size at the end of the freezing season. This has been picked up widely by the (online) media, probably more so because it's the lowest maximum on several records, and possibly the earliest, by a large margin.

NASA has put up a very nice, concise video explaining the whole thing:

Arctic sea ice extent appeared to have reached its annual maximum extent, marking the beginning of the sea ice melt season. This year’s maximum extent not only occurred early; it is also the lowest in the satellite record. However, a late season surge in ice growth is still possible.

I referred to this possibility 5 days ago in the Early record, late record blog post. Since then JAXA SIE has continued to drop, increasing the difference with the preliminary maximum. However, the last two days JAXA reported a total increase of 99 thousand km2, reducing the difference to 137 thousand km2. Here's a quick overview, using the Wipneus home brew AMSR2 regional SIE graphs (see this map for orientation), to see what happened where.

As expected, the Bering and Barents show an uptick in recent days (black and purple trend lines):

The last Sea Ice Outlook of this year has been published. The SIO is now organized by the Sea Ice Prediction Network (as part of the Arctic research program 'Study of Environmental Arctic Change', or SEARCH), and is a compilation of projections for the September 2014 Arctic sea ice extent, based on NSIDC monthly extent values. These projections are submitted by professionals as well as amateurs (public outlooks).

Here's the summary for the August report:

Thank you to the groups that contributed to the August 2014 Outlook. We received 23 pan-Arctic contributions. Of the 23 contributions, some are unchanged from July. The median Outlook value for September extent is 5.0 million square kilometers with a quartile range from 4.58 to 5.22 million square kilometers. The overall range is between 4.0 and 5.6 million square kilometers. The median value for August is increased from the June and July values of 4.7 and 4.8 million square kilometers, respectively. This increase reflects the relatively slower decline in ice extent through August than what had been projected earlier. The overall range has narrowed since July, suggesting that the projections are tending to converge, as one would expect with a shorter forecast period. There were four regional Outlooks submitted with a fairly large range in both spatial extent and ice-free dates. There have not been any significant extreme weather events this summer as was seen during the record low years of 2007 and 2012. The more quiet conditions have likely played a role in the evolution of the sea ice extent this summer. While the extent is far from a record low, all contributions will put 2014 as one of the ten lowest September extents in the 36-year satellite record.

The second Sea Ice Outlook of this year has been published. The SIO is now organized by the Sea Ice Prediction Network (as part of the Arctic research program 'Study of Environmental Arctic Change', or SEARCH), and is a compilation of projections for the September 2014 Arctic sea ice extent, based on NSIDC monthly extent values. These projections are submitted by professionals as well as amateurs (public outlooks).

Here's the summary for the July report:

The median Outlook value for September 2014 sea ice extent is 4.8 million square kilometers with quartiles of 4.4 and 5.0 million square kilometers. Thus, the median value is slightly higher than the June value (4.7) and the distribution of Outlooks is slightly reduced relative to June. The overall range is now from 3.2 to 5.9 million square kilometers. These values compare to observed values of 4.3 million square kilometers in 2007, 4.6 million square kilometers in 2011, 3.6 million square kilometers in 2012, and 5.4 million square kilometers in 2013.

Sea ice declined at a pace more rapid than normal during June, particularly late in the month when extent decreased by over 100,000 square kilometers per day. The decline has since slowed somewhat.

The Sea Ice Outlook is a venue for discussion and networking and provides a transparent exercise in both scientific sea ice predictions as well as estimates from the public. The post-season activities will provide more of a scientific analysis of the methodologies, relative performance, etc.

This month's full report includes the comments on modeling outlooks and on regional predictions, a summary of current conditions, key statements from each Outlook, and links to view or download the full outlook contributions.

And here's the graph to go with the SIO, showing all the predictions (here's last month's version):

So, the median went up from 4.7 to 4.8 million km2, which is logical given the flip in weather conditions that put a damper on the fast declines in the two-three preceding weeks (more on that in the next ASI update this weekend). The highest prediction by Wang using the CFSv2 model went down from 6.3 to 5.9 million km2, though.

No WUWT poll was submitted for this July SIO, so we can't average it with the ASIF poll, which resulted in a predicted NSIDC September SIE average of 4.17 million km2 (up from 3.95 million km2 in June). You can check my spreadsheet with the poll results on Google Drive, to see if I've made a mistake. There will be a new and final poll on the ASIF, come August 1st. Be sure to vote, everyone! Even though there won't be a new record this year, it's still very interesting to see whether 2014 ends up near/in the top 3, or stick with 2013.

Here's some more context, ie the September minimums for the last 9 years (in millions km2, found here):

The first Sea Ice Outlook of this year has been published. The SIO is now organized by the Sea Ice Prediction Network (as part of the Arctic research program 'Study of Environmental Arctic Change', or SEARCH), and is a compilation of projections for the September 2014 Arctic sea ice extent, based on NSIDC monthly extent values. These projections are submitted by professionals as well as amateurs (public outlooks).

Here's the summary for the June report:

The median Outlook value for September 2014 sea ice extent is 4.7 million square kilometers with quartiles of 4.2 and 5.1 million square kilometers (See Figure 1 in the full report, below). Contributions are based on a range of methods: statistical, numerical models, estimates based on trends, and subjective information. We have a large distribution of Outlook contributions, which is not surprising given the different observed values in 2012 and 2013. The overall range is also large at 3.2 to 6.3 million square kilometers. The median outlook value is up from 4.1 million square kilometers in 2013. These values compare to observed values of 4.3 million square kilometers in 2007, 4.6 million square kilometers in 2011, 3.6 million square kilometers in 2012 and 5.4 million square kilometers in 2013. Only three outlooks this year are above the 2013 observed September extent.

As the season progresses, it will be interesting to follow the relative influences of weather (i.e., warm Arctic winter in 2013/2014 and the wind and weather through the summer) and initial conditions of the sea ice, all in the context of the long-term downward trend of sea ice extent.

Here's a re-post of the NSIDC's Greenland Ice Sheet Today website, but let me also draw attention to this wonderful new resource, Polar Portal, set up by various Danish scientific research organisations. It has various maps and graphs depicting the situation on Greenland, but also the rest of the Arctic (weather and sea ice, etc).

---

2013 in review; 2014 melt begins

Figure 1 shows the cumulative number of days that the Greenland Ice Sheet experienced surface melting during 2013 (right image), along with comparison images for 2011 and for 2012, the record year for melt days.

Overall, 2013 melt intensity, expressed as the number of melt days relative to the 1981 to 2010 average, was slightly to moderately higher than average in the southern and western Greenland Ice Sheet but unusually low along the northern and northeastern coastal areas.

In particular, surface melt did not extend to the higher-elevation interior regions in the north as much as has been typical for the 1981 to 2010 period. A narrow band along the eastern coastline showed significantly greater than average melting, but here as well the surface melt conditions did not extend inland and uphill as they have in recent years.

(...)

The 2013 summer in Greenland also saw a reversal of the recent trend in summertime loss of surface snow and ice mass by run-off, as would be expected given the reduced melting. Figure 3 illustrates the relative melt area departure from the average (sum of the daily melt areas over the ice sheet for June, July, and August in each year, with the average area for 1978 to 2013 subtracted). The very large increase in 2012 is clearly shown, as is the return during 2013 to conditions typical of the late 1990s.

Are scientists conservative about sea ice?

Guest post by Walt Meier, NSIDC Scientist

Arctic sea ice set a record minimum extent in September 2012, far
below the previous record low in 2007. Summer extents have been far
lower than average for the last decade, with several record or
near-record years. Looking at the numbers, one is tempted to think that
the Arctic Ocean may reach nearly sea ice-free conditions within just a
few years. But most expert analyses indicate that we’re likely at least a
couple decades away from seeing a blue Arctic Ocean during the summer.

So what is going on here? Readers have asked if scientists are being
too conservative in their assessment of the recent ice loss. We asked
Walt Meier, NSIDC scientist, to address this question. Following is his
response.

As the persistent Arctic cyclone - or PAC-2013 - of the past couple of weeks winds down, I want to discuss what I've found on the subject in a couple of research papers. But first want to refer to two excellent blog posts from last week doing just that, on the Robertscribbler blog and FishOutofWater's blog on Daily Kos.

This animation of DMI SLP maps shows the birth and demise of PAC-2013:

Perhaps I should say near-demise, but the weather forecast says it's basically over for this cyclone. Of course, other cyclones come into play in other parts of the Arctic, but it's not the PAC-2013 anymore. After approximately 25 days of wandering around, weakening and re-strengthening to a pretty powerful cyclone at times, churning ice, keeping the Arctic cold, we've witnessed another remarkable cyclone in less than 1 year's time.

There are a couple of questions that have been on my mind ever since the cyclone started to show itself persistent:

Is PAC-2013 unprecedented?

Is it somehow caused by the progressive loss of Arctic sea ice?

If so, will we see these PACs more often?

What will the effect on the sea ice be, short-term and long-term?

To answer some of these questions I did a search on Google Scholar with summer arctic cyclone as search words. Because the Arctic is changing so fast, I was mostly interested in recent research, but I remembered there was one paper from 2008 that I read last year during GAC-2012, that also has interesting things to say about Arctic summer cyclones. So, I'll start off with that one and quote the most interesting parts.

This guest blog was sent to me by Bill Fothergill, also known by his nom de plume billthefrog. It discusses and takes on the yearly fake skeptic tradition of misleading people into thinking all is fine because ice cover around the maximum (when viewed from above, of course, not from the side) is just as large or even larger than in year X. It's a dirty job, but someone's got to do it. Thanks, Bill!

Another
thrilling instalment in the long running saga of the “Arctic Sea
Ice Recovery”

The Arctic Sea Ice Blog features a
frequently updated set of links to relevant news articles. (Or should
that be “arcticles”?) One of these recently linked out to a blog
hosted by the Toronto Financial Post and written by the redoubtable
Lawrence Solomon. The heading of the piece in question loudly and
proudly proclaimed…

On one level Mr Solomon’s claim is
nothing more than egregious nonsense, but it is nonetheless worth
looking at in order to see how cleverly the misdirection is
perpetrated. (It is also worth looking at his article for no other
reason than to see the somewhat unambiguous feedback provided to Mr
Solomon by a certain Neven Acropolis.)

There are several scientific organisations that keep an eye on the
Arctic sea ice cover and put out graphs to inform us of the amount of
ice that is left. You can see most, if not all, of them on the ASI Graphs webpage. The minimum records on ALL of these graphs have been broken this melting season.

---

We already knew this would happen, so the excitement isn't commensurate with how big a thing this really is, but it's official now: the NSIDC September average sea ice extent record from 2007 has been smashed to smithereens.

Like I've said a couple of weeks ago: You thought 2007 was big when it smashed the 2005 records? Well, 2012 is to 2007 what 2007 was to 2005. If my calculator doesn't deceive me, the 2007 record was a drop of 22.2% from the 2005 record. The 2012 record is a 23.6% drop from the 2007 record. (Edit: I screwed up, mistaking the 2008 number for the 2007 number. Misfratz has the right numbers in a comment below. 22.8% drop from 2005 to 2007 September average sea ice extent, and a 16% drop from 2007 to 2012 September average sea ice extent.)

As you can see the 2007 sea ice area record has also been thoroughly demolished. But the same of course goes for IJIS September average SIE (graph courtesy of Seke Rob):

So now we wait and see if the CT SIA anomaly drops below the 2007 record, and perhaps the CT Global SIA record anomaly is in the works as well (depends on the Antarctic sea ice mostly). Oh, and of course, the PIOMAS minimum volume. The record was broken a while back.

And then we'll watch the freezing season a bit. I'm working on a couple of changes. More on that later...